According to Sky News, del Missier negotiated a deal worth at least £8.75m just before he resigned on 3 July.

The amount is believed to be just over half of a £17m long-term bonus that he was due to receive in March, but was not paid out because Barclays executives said that it was an “inappropriate climate” for such a large bonus to be awarded.

Since he was due to have received the bonus earlier this year before the LIBOR revelations, it is understood that the bank felt there was no legal basis for forcing del Missier to reject the severance cash payout.

Last month, Barclays paid fines adding up to £290m to the Financial Services Authority (FSA), the US Commodity Futures Trading Commission (CFTC) and Department of Justice (DoJ) for misconduct relating to the reference rates at which banks lend to each other, known as London Interbank Offered Rate (LIBOR) and the Euro Interbank Offered Rate (EURIBOR).

The process of setting LIBOR and EURIBOR rates requires banks to make submissions each day based on borrowing and lending between banks. The average of the rates from the submissions are then calculated to produce LIBOR and EURIBOR.

The email, a summary of a phone call between Diamond and the deputy governor of the Bank of England (BoE), Paul Tucker, appeared to suggest that the BoE may turn a blind eye if Barclays lowered its high LIBOR submissions so that it did not look like it was under financial stress during the international banking crisis.

Last year, del Missier was revealed to be the highest paid senior executive at Barclays, earning a salary and bonus of £14.3m in 2010. Including shares, his pay package was worth £47.3m in total.

He joined Barclays Capital in 1997, prior to which he held senior technology, finance and front office positions at the Bank of Boston and the Bank of New England.